Ok, since so many people here have problems with this:
Here is me soldering a pot with a 3-year old 25 watt Radio Shack iron that saw many hours of use before being tossed in a box and thrown in the basement for about a year. I didn't even bother to clean it up and it worked just fine.
Not saying thats the best tool for the job, but its not hard to get a really good joint with a 25-watt iron as long as you give it enough time to heat up.
Steps:
A good pre-heat on the iron. (never use an iron's ability to melt solder directly as an indication of temperature)
While the iron is heating, clean/sand whatever non-wire things you are going to be soldering.
Work your way from largest surface area to smallest. (This is going to use the heat more efficiently and keep you from using a 'cooler' tip on bigger things)
Tin everything first. (makes it easier on you in the long run)